An active matrix type liquid crystal display device includes a liquid crystal display panel, a scanning line drive circuit and a signal line drive circuit which supply signals to be input in the liquid crystal display panel, and a display control circuit that controls the entire liquid crystal display device. The liquid crystal display panel displays images in the following manner, for example: the alignment of liquid crystal molecules contained in a liquid crystal layer enclosed between a pair of transparent substrates is changed to generate a phase difference by applying a voltage between electrodes provided on the liquid crystal layer side of each transparent substrate so as to control the amount of light passing through a polarizing plate provided on the outer side of each transparent substrate. To display color images on the liquid crystal display device, color filters of multiple colors are formed inside the liquid crystal display panel, and these color filters of multiple colors are arranged in juxtaposition for color display.
The liquid crystal display panel includes multiple signal lines and multiple scanning lines intersecting the multiple signal lines. Pixel electrodes are located at these intersections to form a matrix. At each of the intersections, a switching element, such as a thin film transistor (TFT), is provided. The TFT is driven upon input of a scanning line signal from the scanning line drive circuit (also referred to as “gate driver”), and writes the signal line voltage that was input from the signal line drive circuit (also referred to as “source driver”) into the liquid crystal layer through the corresponding pixel electrode. When no scanning line signal is input from the scanning line drive circuit, the previous signal line voltage is held in the liquid crystal layer.
Generally, the liquid crystal display device is AC-driven to protect properties of liquid crystal materials.
Specifically, polarity-reversal driving is performed in which the same voltage of the opposite polarity is periodically applied to the pixel electrodes. The following examples of the polarity-reversal driving have been suggested: frame-reversal driving in which the polarity of the entire panel is periodically reversed; line-reversal driving in which the polarity of each driving line is reversed; and dot-reversal driving in which the polarity of each scanning line and each signal line is reversed. Examples of the line-reversal driving include gate line-reversal driving in which the polarity of each scanning line is reversed, and source line-reversal driving in which the polarity of each signal line is reversed.
In line-reversal driving, the pixel electrodes to which a voltage of the same polarity is applied are linearly aligned, so that display defects, such as streaks, flicker, and shadows, attributable to the difference in luminance may be visible. In dot-reversal driving, the polarity of each sub-pixel is reversed, so that display defects that may occur in line-reversal driving do not occur; however, the concurrent output voltage is twice as high as the driving voltage, so that the power consumption to drive the IC is unfortunately high.
Thus, in order to reduce the driving voltage of the liquid crystal display device, pseudo dot-reversal driving based on so-called staggered input method in which pixels to be connected to the same driving line are displaced vertically and transversely so that these pixels are not on the same driving line has been designed for line-reversal driving (for example, Patent Literatures 1 to 6). Display defects can be reduced by employing pseudo dot-reversal driving, as is the case with dot-reversal driving. FIG. 9 is a schematic plan view of an array substrate of a liquid crystal display device according to Patent Literature 3. For example, in the case of Patent Literature 3, as shown in FIG. 9, a liquid crystal display panel 300 includes multiple data lines Ls and multiple scanning signal lines Lg, wherein the multiple data lines Ls are laid out in a grid form so as to intersect with the multiple scanning signal lines Lg, and multiple pixel forming units Px are provided at positions corresponding to the intersections between the multiple data lines Ls and the multiple scanning signal lines Lg. Rj, Gj, and Bj (j=1, 2, or 3) indicate data signals that are applied to the respective data lines Ls. SS1, SS2, SS3, and SS4 indicate scanning signals that are applied to the respective scanning signal lines Lg. A portion surrounded by dotted lines corresponds to one pixel. In Patent Literature 3, the pixel electrodes to be simultaneously selected, which are pixel electrodes connected to switching elements that are turned on and off by the same scanning signal line, are arranged dispersedly in two pixel rows vertically adjacent to each other and such that a series of three vertically arranged pixel electrodes Px (“upper, lower, and upper” pixel electrodes Px or “lower, upper, and lower” pixel electrodes Px) as a unit is periodically repeated in the horizontal direction. In FIG. 9, “+” and “−” indicate the polarity of a signal to be applied to the pixel electrodes Px. R, G, and B indicate colors (red, green, and blue, respectively) of sub-pixels arranged in positions corresponding to the pixel electrodes Px.